In an electrophotographic image forming apparatus, a charging device charges a surface of an electrostatic latent image carrier (for example, photoreceptor), an exposure device exposes the charged region according to image information to form an electrostatic latent image, and a developing device develops this electrostatic latent image with toner.
This developing device includes a toner cartridge in which toner is stored, and all the stored toner is desired to be used up. For example, Japanese Laid-Open Patent Publication No. 2011-8142, Japanese Laid-Open Patent Publication No. 2010-256557 and Japanese Laid-Open Patent Publication No. 2011-59296 disclose a technology in which a mechanism which locks pulling-out of a toner cartridge so as not to be pulled out by a user easily even when it is detected that there is no toner is provided, in which it is not able to be pulled out unless operation for releasing lock is performed on an operation screen of an image forming apparatus main body.
However, since Japanese Laid-Open Patent Publication No. 2011-8142, Japanese Laid-Open Patent Publication No. 2010-256557 and Japanese Laid-Open Patent Publication No. 2011-59296 have a structure in which a cover of the image forming apparatus main body is locked, there is a problem that, supposedly, when lock of the cover of the image forming apparatus main body is able to be released on the operation screen or when the cover of the image forming apparatus main body is able to be opened, the toner cartridge is able to be detached from the image forming apparatus main body and toner is not able to be used up.